Slide fastener stringer tape reinforcement



Aug. 31, 1943. N. J. POUX SLIDE FASTENER STRINGER TAPE REINFORCEMENT 2 Sheets-Shet 1 INVENTOR.

Filed March 9, 1940 ATTORNEY,

N. J. POUX Aug. 31, 1943.;

, SLIDE FASTENER STRINGER TAPE REINFORCEMENT Filed March 9 1940 2 sheets sheet 2 ATTORNEY;

f Patented Au 31, 1943 uniformity and consequent decrease in the UNITED STATES i PATENT OFFICE I SLIDE FASTENER STRINGER TAPEi REINFORCEMENT Noel J. Foux,,Meadville, Pa., assignor to Talon,

' Inc., a corporation of Pennsylvania 1 Application March 9,1940, Serial No. 323,188

3 Claims.

This invention relates to the manufacture of slide fasteners and,in particular, to the reinforcement of textile or other stringer tapes at the edges to which slide fastener interlocking elementsare to be clamped or otherwise secured.

It is an object of this invention to provide a method of attachment of tape edge reinforcing cords, wherein the cords'are attached most firmly to the stringer tape edges. i a It is a further object of this invention to provide a method wherein .the attachment to the stringer tape edges of oppositely wound edge reinforcement cords is accomplished with relief of internal torsional stresses in the attached tape I edge reinforcement cords. I

His 9, further object of thisinvention toprovide such a method wherein the tape is exactly concentrically'disposed with respect to the cords at opposite sides or, in other words, wherein the cords are of equal size because of equal compression thereof.

It is a further object of this invention to eliml- 'nate peeling-of the cords from thetape after the attachme t of slide fastener interlocking elements to the reinforced tape edges because of the elimination of torsional stresses in the. reinforcing cords prior to attachment of the slide fastener interlocking members.

It is a further object of this invention to provide for increase in the compression in the cord reinforced edge of the stringer tape and to secure xed tape radius which advantageous features are incidents cf the compression, to the same degree,

of both cords applied to the tape.- These and other objects and advantages of the invention will appear from the following descrip tion-taken in conjunction with the accompanying. drawings which form a part thereof,'and will be pointed out in the appended claims,

' In the drawings:

Fig. 1 is'a view in perspective, and partly in cords, a single line of stitching extending through the cords and the intervening tape edge has been used for attaching the cords to the, tape edge,

tially on the line i.i0 of Fig.9; Fig. 11 is a view similar to Fig. 9, but showing staggered double stitching; and

:tially on the line l2.-i2 of Fig. 11.

ing the secondor added sewing step of this invention;

Fig. 6 is a transverse section .taken substantially on the line 66 of Fig.

, Fig. '7 is a plan view. of a double-sewed cord reinforced asillustrated in Fig. 1; with inter- Fig. 8 is a transverse section similar to Fig. 4, taken substantially on the line 8-8 of Fig.7, and illustrating the elimination of peeling by the double sewing of the cord according to this invention; v

Fig. 9 is a plan view of double stitched cord reinforced stringer tape, wherein the stitching is looking fastener members attached thereto;

" superposed Or substantially in line;

Fig. 10 is a longitudinal section taken substan- Fig. 12 is a transverse section taken substan- In former methods of reinforcing the slide "fastener interlocking member supporting-edge of stringer tapes by theattachment, at opposite sides thereof, ofoppositely wound reinforcing see Fig. 1.

In such methods the upper reinforcement cord is compressed to a greater degree than the .lower reinforcement cord due, no doubt, to the fact that the needle stresses the upper thread to a higher degree than does the bobbin stress-the lower thread. Y

In many cases, this causes the interlock of the upper and lower threads to deviate from the exact central axis of the .intervening tape. Likesection, illustrating the initial sewing step of this invention; 1

Fig. 2 is a,transverse section taken substantially on the line 2-4 ofFig. 1;

Fig. 3 is a longitudinal section taken substantially on the line 3--3 of Fig. 2;

Fig. '4 is a view similar to Fig. 2, but showing a known form of slide fastener interlocking member attached to a cord reinforced stringer tape wherein the attachment is-achieved by 'a single sewing step, as shown in Figs. 1, 2 and 3; g

Fig.- 5 is a view similar to-Fig. 1, but illustratwise, the line of stitching is, quite often, spaced y from the longitudinal axis of the cords. This,- in addition to the action of the needle, recipro eating feed dog and stationary throat plate of the machine, causes internal torsional stresses to be applied to the respective cords which are wound in opposite directions or, in other words, clockwise and counterclockwise, as seen in Fig. 2.

When a slide fastenerinterlocking member is clamped or otherwise applied to the attached r'einforcement cords, these cords which are under internal torsional stresses, will tend to'nnwind upon dissipation of temporary torsional stresses in such manner that the interlocking fastener is thrust outwardly from the reinforced edge, as shown in Fig. 4. This substantially impairs the firm" attachment of the interlocking fastener member upon the reinforcement tape edge, and is known as peeling. a The interlocking fastener pation of the internal stresses in the cords will *tend to cause them to unwind in such manner as member, as shown in Fig. 4, is not concentric with respect to the tape due to the greater compression and consequent lesser size of the upper tape edge reinforcement cord, as compared with the. lower tape edge reinforcement cord. These highly disadvantageous features of cord reinforced-stringer tapesproduced by prior known nated 23.

. the reinforced ,tape edge. Likewise, the compression of the reinforced tape edge is increased whereby the difference in length-between the reinforced tape edge and the unreinforced tape cident to peeling were prevalent infasteners to thrust the slide fastener interlocking member 26 outwardly of the tape 2|, as clearly shown in'Fig. 4. As aboce described, this is known as peeling and materially impairs the secure attachment of the slide, fastener interlocking members on the tape 2|. As former methods of reinforcing cord attachment terminated with the above described single sewing step, the defects inmanufactured from tapes so reinforced.

According to this invention, the above-dc scribcd initial step constitutes merely a part of the stringer tape reinforcing method, instead of the entiremethod. According to the method of this invention, the continuous stringer tape 2| with edge reinforcement cords 22 and 23 attached by the single first line of stitching (comprising the first needle thread 24 and the first bobbin thread 25) as shown inFig. 2, is subjected to a second or reverse stitching step. This second or I reversed stitching step is illustrated in Fig. 5.

edge is emphasized or, in other words, the fixed radius of the stringer tape is reduced. As the flexibi ty of the stringer tape in the finished fastener aries inversely with the fixed radius of the tape, any decrease in the fixed radius" of the stringer tape is accompanied by increased flexibility of the stringer tapes and consequent improvement inthe easy running properties of l the fastener.

Referring to the drawings in detail and with reference particularly to Figures 1 to 4, this invention may be carried out with conventional sewing apparatus such as the machine shown in Fig. 1; having an operatinghead II with recip-- rocating needle l5, and provided with a, presser foot l6 having a reinforcement cord accommodating channel H for accommodating that tape edge reinforcement cord which is uppermost in the first sewingstern The machine is provided with amovable feed dog l8 which is surrounded by a stationary throat plate l9 having a suitable trough-like channel 2|lffor accommodating that tape edge reinforcement cord, which is lowermost in the first sewing step. The tape is designated 2|; the tape edge reinforcement cord, which is uppermost in the first sewing. step, is designated 22, and' the tape edge reinforcement cord, which is lowermost in the first sewing step, is desig- The needle I5 carries a thread and the bobbin carries the thread 25. These threads are interlocked in a lock stitch, as shown in Figs. 2 and 3. The needle thread 24will' be hereinafter referred to as the first needle thread and the limbbin thread 25 will be hereinafter referred to as the first bobbin thread for reasons which will hereinafter most clearly appear. When most ideal conditions exist, the interlock of the threads 24 and 25 will occur centrally of the plane of the I tape 2|, as shown in Figs. 2 and 3. The threads 24 and 25, however, will rarely pass directly through the centers or longitudinal axes of the reinforcing cords 22v and 23, but will' generally pass to one side thereof, as shown in Figs. 2 and4.,

As shown-in Fig. 4, when the legs of the slide fastener interlocking member 26 are clamped upon the attachedtape'edge reinforcing cords shown in Fig. 2, the cords, which are oppositely wound, as described above, will tend to seek a state .of equilibrium wherein the applied internal torsional stresses are dissipated. This dissi- Asshown in Fig. 5, the stringer tape 2| and at- 0 tached cords 22 and 23, with the first line of stitching 24, 25, is again run between the presser foot |6-and the feed dog I8 and throat plate IS. The cord 22 (which was uppermo t in the first stitching step) is now the lower ost cord and is guided in the channel .20, as. shown in Fig. 5. The cord 23, which was formerly the lowermost cord (nowinverted) is attached by the first line 7 of stitching to the stringer tape 2| and the channel ll of the presser foot H5 is, therefore, inoperative in the second stitching step. The needle |5 carries the second needle thread 28 and the .bobbin carries the second bobbin thread 29. In the second stitching step, the second line of stitching 28, 29 is formed by the second needle thread 28 and the second bobbin thread 29 and, necessarily, the inequalities in tension between the needle thread and bobbin thread are reversed in the second line of stitching 28, 29, as compared with the first line of stitching '24, 25. The inequalities in compression between ,the cords 22 and 23 are, therefore, equalized and the cord thickness is uniform, as shown in Fig. 6.

As will be readily understood from the showing of Fig. 8, the stringer tape 2| is disposed-con centrieally with respect to the cords 22 and 23, therefore,concentrically with respect to the attached slide fastener interlocking members 26,- asshown-in Fig.8. Furthermore, as-will readily appear from comparison of Figs. 4 and 8; the tendency for uritwisting the cords 22 and 23 to cause peeling is "effectively prevented by the.

two lines of attachment provided by .the .stitchings 23, 25 and 28, 29. :.Peeling is thus pre- I vented. '.While the' showing of Figs. 5, 6- and 7 presupposes that the lines 24, 25 and 28, 29 of stitching are straight and parallel, nevertheless, under some conditions of operation, these lines 'of stitching may be superposed or disposed in line. This condition is illustratedin Figs. 9 and 10. From Figs. 9 and 10, it will clearly appear that the inequalities between the compression of the respective cords 22 and 23 are eliminated, as the difference in thread tension between the first and second lines of stitching will neutralize or balance one another.

In addition to the above-described conditions,

24, -25 and 28, 291113.37 be zigzag,"

the stitches" which condition is illustrated in Figs. 11 and 12. In this condition also, the inequalities in thread tensions between the first and second lines of stitching are also neutralized or balanced and the compression of the cords 23 and 22 is equalized.v a

As will clearly appear from the above description, the use of two'lines of stitching to secure the reinforcement cords 23 and 22 through the edge of tape 2| increases the compression of the cords-23, and 22 over the compression achieved by a single line of stitching, as illustrated in Figs. 1 to 4; The added compression or these cords likewise increases the difference in length between the free, unreinforced edge of the stringer tape 2| and the reinforced edge thereof, or, in other words, decreases the fixed radius thereof. This increase in difierence in length between the tape edges or decrease of the fixedradius, increases the flexibility of the complete fastener andmaterially increases the smoothness with which the fastener interlocking members 2| are engaged and disengaged.

It will thus be seen that, according to this invention, the flexibility of the'fastener, tapesis increased, the security of attachment of the fastener interlocking members 28' to the tape is substantially increased and complete concentricity of the stringer tape 2l'with respect to the cords 22 and 23 and with respect also to the attached fastener interlocking elements is secured. The security of attachment of the fastener interlocking members 26 with respect to parting to the tape a fixed radius, inverting said fact that the impairment of the acuteness of the radius placed in the tape by. the first line of stitching 24, 25 is prevented by the locking actio of the second line of stitching 28, 29. i

In addition to the locking action of the second line or stitching 28, 29, this line of stitching, by increasing the compression of the cords 22 and 23 and equalizing the compression of the respective cords, increases the acuteness and uniformity of the fixed radius throughout the length of the tape.

. It is, of course, to be understood that the above description is merely illustrative and in nowise limiting and that I desire to comprehend within.

my invention all modifications included withinthe scope of the appended claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1.In a method of reinforcing slide fastener stringer tape, attaching oppositely twisted edge reinforcement cords to opposite sides of one edge of a stringer tape by a single line of lock stitching applied from one side ofthe tape while imtape, and resi'stitching said cords to said tape the tape is secured, as above described, through elimination of "peeling" byattaching the cords '22 and 23 to the tape edge without production of torsional stresses therein.

From another aspect, it may be stated that the function of the first line of stitching is to impart a tempora yflxed radius to the continuous tape, while the function of the second line.

of stitching is to increase the acuteness of this fixed radius and lock it into the tape, or render it permanent. 'In this manner, the fixed radius edge by a second line of lock stitching applied from the opposite side of the tapeto lock the fixed radius in said tape. 7

'2. A new article for use in the manufacture of slide fastener stringers comprising a tape, a pair cfoppositely wound cords at opposite sides of one edge of said tape, and a pair of lines of stitching extending through said cords and saidtape; the

needle threads of each line of stitching being disposed at opposite sides of said tape. i

3. In a method as defined in claim 1, said lines of lock stitching-being parallel and spaced at opposite sides of the longitudinal axes of said cords.

NOEL J. POUX.

of the tape is substantially decreased due to the 

